It is well known that deck harnesses are provided on boats and ships for safety whilst on deck. A deck harness facilitates the attachment of the wearer to a strongpoint, for example a jackstay by means of a tethering line or strop whilst on deck. It is common that many mariners consider the use of a deck harness to be uncomfortable and restrictive and more particularly they find such harnesses difficult to don and adjust. As a result, many disregard the hazards associated with not wearing the harness and choose not to wear them whilst on deck or postpone donning at risk to themselves until conditions worsen and donning is more difficult. Furthermore, as the means of adjusting a typical known harness can be difficult and slow to use, in lively weather, users may incorrectly adjust the harness or fit it wrongly resulting in greatly reduced protection of the user.